Luminescence shift of electrospun ZnO/MEH-PPV/PEO composite nanofibers

The photoluminescence characteristics of electrospun ZnO/poly[2-methoxy-5- (2-ethylhexyloxy)-1,4-phenylenevinylene]/poly(ethylene oxide) (ZnO/MEH-PPV/PEO) composite nanofibers with various composite ratios of ZnO nanoparticles (NPs) and MEH-PPV are investigated in this study. The photoluminescence spectra of the nanofibers show sequential red- and blue-shifts in the peak wavelength with increasing concentration of ZnO NPs. For the nanofibers in which their concentration is relatively low, the dispersed ZnO NPs induce the aggregation of MEH-PPV, resulting in the red-shift of the peaks. In contrast, for the nanofibers with relatively high concentrations of ZnO NPs (over 50%), the blue-shift of the peaks occurs. The mechanisms of the red- and blue-shifts are discussed in this paper.